Apparatus for wireless telegraphy and the like.



P. E. EDELMAN.

APPARATUS FOR WIRELESS TELEGRAPHY AND THE LIKE-' APPLICATION FILED AUG- 19' 1912.

Patented Jan. 30, 1917.

2 SHEETSSHEET 1.

zLzEmuM/ac- NET 47 MOTOR WITNESSES: 7%W 1W 11v VEN TOR.

v PIE. EDtLMAN. APPARATUS FOR WIRELESS TELEGRAPHY AND THE LIKE.

APPLICATION F'ILED AUG. |9 1912- I I I 4 1 214 022, I Patented Jan. 30,1917.

2 SHEETS-SHEET 2- J'NVENTOR.

' at Minneapolis,

FHILIP E. EDELMAN, 0F MINNEAPQLIS, MINNESDTA.

APPARATUS FOR WIRELESS TELEGRAPHY AND THE LIKE.

Specification of Letters Patent.

Patented Jan. 36, 1917.

Application filed au ust 19, 1912. Serial No. 715,850.

To all whom it may concern:

Be it known that I, PHILIP E. EDELMAIN, a citizen of 'the United States, residing in the county of Hennepin and State of Minnesota, have invented a new and useful Apparatus for Wireless Telegraphy and the like, of which the following is a specification.

My present invention relates to wireless space communication or control and has for one of its objects the perfection of the prior 'art to overcome defects, anong which the following may be mentioned: 1. Slow rate of communicatlon. (Words per minute.)

2. Unsatisfactory selectivity of apparatus.

3. Injurious interference. 4. Lack of secrecy.- 5. Inability to utilize mechanical recorders satisfactori y. 6. Drowning of signals by static interferences. 7. Confusion of signals. 8. Inability of several nearby stations to'work continuously and independently. 9. Non-precisive apparatus. 10. Impediment of highTesistance detectors and circuits to oscillations; Q

My invention provides a system of communication or control which is practically free from interference, space tapping, static disturbances, and other defects. The apparatus used is not complicated and is reliable.

My invention is more particularly pointed out in the appended claims but in general I prefer to transmit integral parts of a code message differentially, making it practically impossible for. an unauthorized station to intercept the message. Moreover, I prefer to replacethe dashes of the code by dots to increase the; speed of transmission. It will be obviousof course that the regular dot and dash code may be used if speed is no object, or the dots may be replaced by dashes lf'accuracy and clearness are essential. It is a common occurrence in the prior art to have a message repeated two or three times slowly before it is accurately received, a method which consumes valuable time. In accordance with the to divide a given signal into a plurality of recognized groups, and to transmit the integd-al parts inagnanner which distinguishes each part a plurality of separate characteristics, astnne duration, audible group he quenyfiand radio frequency, the latter of course determining a characteristic wavelength,

and preferably two I or a combination of all of these means.

' system is referred present invention I'prefer In order to carry out this invention 1 rovide novel means hereafter fully .descri ed.

It is understood that my invention is applicable to all forms of communication or control in which electric waves are utilized, although the embodiment in a signaling to in particular. This invention will be better understood by referen'ce to the accompanying drawings, in

which Figure 1 shows a suitable embodiment of 1 the transmitter and is partly a vertical section of the electrode element used to produce suitable oscillations and partly a diagram of a suitable circuit therefor. Fig. 2 is a diagram of a modification of Fig. 1. Fig. 3 is a detailshowing the face of the rotating disk of Fig- 2. Fig. 4: is a diagram showing another "modification of Fig. 1. Fig. 5 is a schematic diagram showing a suitable embodiment of the receiver. Fig. 6 is a diagram showing another modification of F ig. 1. Fig. 7 is a diagram showing another modification of Fig. 1. Fig. 8 is a diagram showing a modification of Fig. 5.

ig. 9 is a diagram illustrating the function of part of the ClZ'CIlli; shown in Fig. 8. Fig. 10 1s a diagram showing another modifica tion of Fig. 5. Fig. 11 is an elevationshowing the segments on one of the electrodes shownin Fig. 0f. the rotary electrode of Fig. 1 showing the two sets of segments embodied therein. Fig. 13 is an elevation showing the other stationary electrode of Fig. 1 provided-with segments. Fig. 14. is a diagram of a further modification of Fig. 1 whereby a blind signal may be transmitted. Fig. 15 is a diagram of a further modification of Fig. 5'.

Fig. 16 is a diagram of another modification 1. Fig. 12 is a sectional view 1 my invention. 20 is a front elevation partially in 660- matic diagram showing a modification of the rotary tuning means shown in Fig. 5. Fig. 22 is a diagram showing a further modification of Fig. '5.

Similar reference characters-refer to similar parts as far as is consistent with 'clezii ness.

In Fig. 1, 1 represents the aerial or antenna system, 2 the ground system, 3 an 1 nductance coil having two inductance co1ls 7, 8, respectively coupled magnetically therewith, and 4 is an insulated switch inagnetically operated by 11 pulling armature 12 connecting therewith and spring restored by spring 5, whereby the insulated switch arms 1, 6, respectively contact with the positionsja or 6 according to whether key 9 or 9" 1s closed. A generator 10 also connects to the double discharge gap 17 thrpugh 14, gap G, and 13 or 14, gap Gr, and-13 respectively when 9501 9 is closed. .17consists of electrode 22 carried by shaft38and rotated by motor 20 via pulleys 18, 19 between and in close proximity to stationary electrodes 21, 23. These electrodes mayybe of any suit-' able conductor or metal and while thesurfaces thereof may be smooth they are prefer"- ably segmented as indicated by Figs-11,512 and 13, in order. to impart a plurality of recognizable audible group'frequencies to the transmitted energy. These electrodes are inclosed by a casing 32 and are preferably operated in the presence of a gas supplied by 39 connecting therewith or a thin oil which may be supplied via the oil cock '38 also connecting therewith. The gas is preferred and is best supplied under a definite pressure. This gas should preferably contain hydrogen but may be ammonia or carbon dioxid. 39 indicates the gas supply connecting with 32 through suitable valves 40 and -10. These valves are old and well known, -10 serving to control the pressure of the gas admitted to the interior 31 of easing 32 and 10 serving as a relief valve to avoid excessive pressure therein- Shaft 38 is mounted in 32 as shown to avoid leakage of the medium supplied to the interior 31 as hereinbefore set forth and is also provided with end bearings p, p, respectively to 'pi'event side play and insure accurate adjustment of the gaps G, G. 21 and 23are substantially of similar construction except that when provided with segments the one has a greater number of segments (Fig. 11) than the other (Fig. 13). These plates are insulated from each other and from the casing 32 and shaft 38 as shown. Insulating flanges 33, *3 respectively support these plates 21. 23 and are in turn supported by metallic flanges 34, 34 respectively carried on screw threads so, 36, by 35, Elfi -attached to 32. it is understood that screws and utlu-l' fasteners are omitted for the sake of dearn ss. The screw threads 36 enable the gaps (Q. (11 "to be closely adjusted. The

plates and su 'iports are preferably substan zall :onstr utml and the plates in particuouhi have a large radiating surface. bearings, while constructed to prevent ltzihtlfle of the gas or oil which may be introduced in 3] set forth also serve to for plates 21 and 23.

connected in circuits as shown.

maintain the shaft in accurate alinement. The flanges supporting plates 21 and 23 should be of a size which will afford rigidity and strength. Metallic plates 26, 27, 28, 29 respectively mounted on insulation 30, 30 and 30 form a partial bearing and support 26 and 27 also serve as connecting plates to 21 and 23 via flexible conductors 24 and 25, whereby 21 and 23 are The gaps G, G are made very minute, as forexample .0075 inch. The double gap discharger 17 is well cooled in any case and the conditions essential for the production of well sustained oscillations are provided.

The-rotating electrode '22 preferably has each of its two fiat surfaces segmented to correspond respectively with the segments provided on 21 and 23, as indicated by Fig. 12. The segments on 21 and 22 forming gap G are understood as substantially identical in construction and uniformly disposed on said plates as shown. The same holds true for the segments on the other side of 22 and on 23 except that there is a different number of segments 'as indicated by Figs. 11, 12. and 13 whereby a different musical tone is secured when energy is passed through G than when passed through G.

The plates 21, 22, are similar in dimensions as shown, Fig, 13 for example representing the segments on either 22 or 23 but a smaller shaft hole indicated by the dotted circle of Fig. 13 is of course provided in 22 to fit shaft 38: while larger holes are provided in the stationary plates 21, 23 as shownby the full line circle, Fig. 13 and Fig. 11. The section of Fig. 12 is accordingly taken along the curved cut a-b, c-d,

respectively of Figs. 11 and 13 in order to show clearly the difference in the segments on the two surfaces of plate 22.

In use the oscillatory circuit through 17 is either through condenser 15, 7, and G, or 15, S, and G, according as 9* or 9" is depressed. Adjustments are made accordingly so that when 9 is depressed energy is radiated from circuit 1, 2, 3, in one definite wavelength and in one distinct audible group frequency, via 7, 15, G, and 13, 14, 10, 9". and another different distinct wavelength and audible group frequency when 8)" is depressed. In the latter case energy is radiated by circuit 1, 2, 3, via 8, 15, G, and 14. 13, 10, f)". The adjustment is further preferably made so that switch 4 is always in either position a or b before energy reaches its blades '6, 6, thereby making the contacts of switch 4 without injurious sparking or arcing.

It is thus obvious that when energy is transmitted by depressing key fl it can only be received at a difl'erent wavelength or tune or both than when transmitted by depressing key 9". 16 indicates a switch .-energy as regards its wavelength by inbe sent as another dot by depressing 'mary circuit 49,- 15, 7 -pled to v:radiating circuit 1, 3, 2.

.When 9 isused the energy to'control motor 20. 37, attached to 32 is a suitable support for the bearing ,1) on the pulley side of 17. v

I prefer to send a regular code message all in dots with this arrangement. Thus in the Word age, the dot of the a can be sent by depressing 9, and the dash egg The other letters are similarly divided through the-two circuits. Or again, one complete word may be sent by the use of 9 and another by the use of 9", alternately or in any desired order. Similarly in a Word like Patent the first three letters can be sent by means of 9 and the remainder by 9". Numerous variations and modifications are obviously possible in this method andapparatus. 9 and 9 may be comprised by any of the well known forms of automatic circuit closers.

In the modification of Fig. '2 the same result is accomplished by using an alternator 10 and a :singleprimary inductance 7 in connection with a'double rotary spark gap 46. The latter consists of a motor driven disk 46 carrying two independent sets of equally spaced projections 44, 45 respectively opposite stationary electrodes '42, 43 either of which is connected in circuit by switch 4 as before. Fig. 3 shows how the projections 44, 45 are arranged on 46. Contactmay be made with the shaft 47 of motor 20, Fig. 2. The adjustments rfire made to secure the same result as beore. Another modification of Fig. 1 is shown m Fig. 4, where a double rotary gap comprised in two separate disks 46", 46 driven by motor 20 and each containin a different number of equally spaced pro ections 44*, 45, respectively, is used according to the method previously set forth andswitch 4 which has a single. contact lever 6 is mechanically connected to key 9' and manually operated thereby to alter the emitted cluding the shunt condenser 48 when 9" is depressed but not when 9 is used. In other respects the circuit will be readily understood. v

A modification of Fig. 1 employing a high frequency enerator 49and utilizing the switch 4 to 'rectly' or inductively cou-v ple primary. circuit 49, 15, 7 circuit"1,3-, 2 in the manner indicated according to whether 9 or 9 is depressed, is shown by Fig. 6. When 9 is used, priis inductively cou- Obviously the wave generators of the preceding figures may be comprised by 49 which indicates any suitable wave generator. is directly transferred to inductance coil 3 and radiated diflierently from 1, 3, 2. I

to radiating the wavelength and audible In the modification of Fig. 7 a suitable source of energy 49, 15, 8 is continuously coupledv to the radiating system 1, 2, 3, and 1 ,musically toned vibrators 5, .51 operated by buzzers 50, 509- respectively and controlled by connection through 9 and 9" as before are used to not only alter the wavelength of the emitted energy but also break it up into distinct group frequencies recurring at an audible rate. It is of included in 1, 2, 3, is altered the wavelength is correspondingly changed.

In the modification. of Fig. 14 a key 9 is provided in addition to keys 9 and 9" to permit a third differentiation or the transmission of a series of blindsignals to confuse would-be space tappers. The buzzers 52 52, 52 cause the respective contacts 53*, '53 and 53 to vibrate at different rates according to the key pressed'and the me arranged adjustment; the result being the same as has already been set forth.

Those skilled in the art will understand that any change in the inductance or capacity of the radiating circuit correspondingly alters the wavelength of the emitted energy. It will further be understood that all the usual precautions as regards insulation and similar engineering details are to be observed in using my invention. It is further obvious that a wide variety of tones and wavelengths are aflorded by the means- .I have hereinbefore described. Single muidentification secured. The use of an undamped wave generator or at leastone of the quenched discharge type, as described,

is preferred because difiiculties from double radiations due to undesired coupling efi'ects are thereby avoided.

It is obvious that if distinctions in signal parts by means of different audible group frequencies alone are used anyone can get the signals the same as the desired parties. Again if a change of wavelength alone is relied upon the benefit of variable audible group frequency distinctions is neglected and confusion can readily result to the desired party as well as others. Thus while either can be used alone under favorable conditions the combination of variations in both group frequency is substantially essential. I It should be noted that my invention requires no synchronously running parts at the transmitting and receivlng stations.

Synchronous running parts are at present an impossibility because 3o course understood. tha when the inductance 7 other disturbances.

they cannot be practically operated between Widely separated stations. Moreover the means I show are adapted for use with energy to secure communication over great distances as contrasted with apparatus of laboratory dimensions as for example transmitters employing spark coils with interrupters on direct current supplies. hforeover a single radiating system suffices, two separate radiating or antenna systems at each station being unnecessary.

In accordance with my invention 1 provide novel receiving apparatus to cooperate with the transmitter to secure the full benefits thereof With a very minimum of interference from other stations, atn'iospheric and l'leretofore the chief reliance in receiving practice has been put in stationary inductance coils loosely coupled to v each other and each tuned to one certain wavelength. Those familiar with Wireless operationhowever know that such coupling effects fail in practice to prevent interferences because the same coupling between the coils which transfers desired energy repre senting signals also transfers stray electrical impulses. lily invention accordingly enibraces means to not only select the desired energies but also to prevent injurious interference from undesired energies also coming to the receiver. I do this by providing separate means to care for each distinguishable form of energy which in practice is found to reach a receivin station. I recognize the natural distinctions in these several energies and take advantage of the natural characteristics of each to select out the desired energies to the exclusion of the others to a practicable extent.

A simple form of receiver suitable when little interference is met with is shown in Fig. 8. The absorbing circuit 1, 3, 2 is supplemented by a condenser 57 shunted about a portion al to e of 3 which is different from the portion 0 to 7 connecting with 1, l, whereby the circuit is rendered particularly receptive to waves of two distinct wavelengths as indicated respectively by A and B, Fi 9. In effect two resonant circuits are formed in a. manner which permits the selection of energy from either one. one circuit comprising 1, c to f of 3, and 2 resonant to a frequency as B, Fig. 9, and the other comprising a circuit 1, 0 to (1- of 3, the reactance formed by 57 shunted about {Z to c of 3' and the portion (Z to c of 3", and the other portion 0 to 7' of 3 in series therewith and 2, resonant to a frequency of greater period as A. Fig 9. This differs from the shunt arrangements of the prior art in receiving apparatus in that 57 is shunted about a por tion only of 3" which is different from the portion connecting with 1 and 2 whereby a doubly resonant circuit is in effect formed whereas formerly where a shunt condenser has been used it has invariably been shunted about the same portion of the inductance, as 3, c to f, as "was included in circuit with the equivalent of 1, 2. In the connection of the prior art the absorbing circuit is accordingly resonant particularly to a single frequency instead of two frequencies as in this arrangement though of course other frequencies will in any case be able to pass through the ab sorbing circuit. In general then any energy reaching this absorbing circuit will be able to pass therethrough but two particular frequencies as A and B, Fig. 9 (it being remembered that a. wavelength determines a frequency and vice versa) will find a circuit resonant thereto, whereas if c and (Z of 3 were made to coincide and c and f were madeto coincide as in the prior art the same would hold true except that frequency A would for example have a resonant circuit While B would not. This arrangement further differs from prior circuits formed by a separate inductance equivalent to 0-cZ of 3 in spries with a reactance formed by another nductance equivalent to Z-e of 3 shunted by 57, in series igrith another separate inductance equivalent to 3-7 of 3 because in such case the two frequencies as A. and B, Fig. 9 could not be inductively transferred as shown in Fig. 8, a circuit through inductance 81 resonant to one frequency as A. Fig. 9 being coupled to 3 while another inductance 81 also coupled thereto is included ,by a circuit ad usted to resonance for the other frequency as B, the single inductance coil 3 serving to transfer both frequencies in the arrangement of Fig. 8. But'other energies reaching the absorbing circuit in greater and lesser Wavelengths will also be absorbed though a resonant circuit is not provided through any portion of 3 therefor. Such stray energy will in turn be trans ferred to circuits included by 81 and 81 but not being comprised in frequencies the same as either A or B can be absorbed as shown in Fig. 8. Thus an absorbing circuit comprised by condenser 57 shunted about portion of 81 can be made resonant to a fre quency lower than A While a similar absorbing circuit through 5"" shunted about a portion of 81 can be made resonant to a frequency higher than B. Such stray energies as are also transferred by the circuits through 3 but in frequencies different from ice am n

sensitive crystal 82 which contacts with a plurality of electrodes or metallic points 77 about at least two of which a device-such as" the inductance 7601' condenser 76 is preferably shunted. Receivers 7 9 and- 7 9 are connected about-78, 78 as shown so that when thetransmitter, Fig. 1, is operated by key 9 the transmitted energy will be received in its distinct audible group frequency in 79' and not in 7.9 and vice versa when 9 is depressed, so that sound waves forming an intelligible signal are received as sent by the transmitter; The function of the devices 76 or 7 6 comprised in the wave detector is to increase the etliciency of this portion of the receiving apparatus. The crystal 82 may foriexample be galena and the several el ectrodes 77 may be placed in contact therewith as indicated in lig. 20. The devices 76, 76 serve to both decrease the effective resistance altered by the wave detectors 78, 78, and also are found to. increase the sensitiveness of 7 8 78-, due probably to reinforcing resonance effects produced thereby. For example, en-

' ergy may accumulate ini 76 and be discharged through 79 in time unison with the rectified current also supplied thereto by the wave detector 78 the net effect being a reinforccment of the sound waves emitted by 7 9 These auxiliary resonance members 76, 76?

are best determined as to size empirically.

1 and do not form an essential part of the tuning means at the I'6C61V1I10' station as for ex ample'the condensers 74?,34, do. From the discussion of this simple circuit it is evident that the embodiment shown by Fig. 5, which aims to secure the same result under more complex conditions often met with in practice, will be understood.

Firstly a double absorbing circuit is afforded byeach of the two branches 1, 80, 54 with shunt 57 :2, and 1, 80, 55 with shunt 57, 2, whereby after the manner already set forth this double shunt circuit comprising the two double absorbing circuits aforesaid can be made resonant to each of two separate frequencies. Also stray energies absorbed in this double shunt circuit will be largely dissipated by dividing, in the two 50. inductance coil 58 wound in the form of ring'armature and carried rotatably by shaft? branches and opposing their effects. The

mounted in bearings 64, 64, forms a closd circuit through condenser 59 and is inductively coupled to both 54 and 55 which are adjustable inductance ,coils whose couplings may be varied by moving them-by means of screw adjustments 56, 56 This closed circuit 58 59 is analogous to the shunt absoroing circuit comprised by 57 shunted about a portion of 81 in Fig. 8 and will absorb frequencies to which it is resonant or nearly resonant. Now adjustable taps 83, 84 arerespectively connected to slip rings 60, 61 connecting with collecting brushes 62, 63 which are connected to condenser 74,-

thereby forming two circuits respectively resonant to two separate frequencies each of which is higher than the frequencies for which the closed circuit 58, 59 is alone riisonant. One of these latter, circuits comprises 74, a portion of 58, and 59 and may be adjusted to one of the desired wavelengths. The other circuit comprises 74:, and a portion of 58 but not 59. [A further circuit is \comprised by 7 4: in seribs with the reactance formed between terminalsi'83, 84: by the divided portions of 58, one of which .contains 59.

My multipoint detector 78 connects with 74 through condenser and has the telephone receivers 79 sh ted thereabout in the usual manner. It i obvious that resonant circuits are provided such that each of two energies of difier'ent wavelength as transmitted in accordance with my invention and reaching this receiver will be transferred to the detector 78 and translated into sound waves by the telephone receivers '7 9 shunted thereabout, while other energies comprised in the form of alternating currents of greater and lesser frequencies when they pass through inductance 80 can be absorbed largely in'57, 57 and in the closed circuit 58, 59 without being recorded by 79. This will be better understood by reference to Fig. 19 where A represents one desired energy and B the other, while C represents an interfering impulsecaused by another transmitter from which signals are not desired. D represents stray impulses reaching the receiving station in the form of irregubymeans of a resistance 71, 58 maybe revolved at any desired rate to take care of most stray energyof the type represented by E, Fig. 19, which energy of course 1s able to transfer itself into any of the circuits, as well as any-of the other undesired energies not otherwise cared for.

ables the desired energies to be transferred to 79 but neutralizes such undesired energies as are not otherwisecared for in the manner set forth. 58 is of course preferably an an core inductance. The rotation is thought to have the effect of dividing undesired unilateral impulses so that they are absorbed in This is considered to be due to the rapid rotation which en-' one of the aforesaid circuits without afi'ecting 78 or 79. The rotation further im proves the selectivity of the apparatus.

In addition-to the energies represented in Fig. 19, strong charges of static electricity may at times accumulate on 1 and set up relatively high pptential disturbances in the receiving apparatus. I therefore provide a static killer to take off such charges and intermittently provide a short path therefor around the receiving apparatus at a rate which does not prevent the normal reception of the desired energies. \Vhen therefore such disturbances are met with the switch '73 may be closed thereby providing a path from 1 to 2 through 73, 72, intermittently as the disk 85 is rotated via pulley 68 by 67 in close proximity to a similar disk 72, both 72 and being constructed with a plurality of alternate conducting and insulated surfaces such for example as indicated by Fig. 18, where 87 represents the insulated segments and 86 the conducting segments therebetween. The adjustment may be such that the conducting surfaces 86 on each plate 85, 72 either come very close to each other or else touch each other intermittently, being effectively separated and insulated from each other when opposite to the portions 87 of the other disk 72 or 85 as the case may be. The effect is that charges accumulating on 1 are cared for as soon as they occur by the direct short path provided through 72, 85 at a very rapid rate and that inasmuch as the rotary tuner 54:, 55, 58, is only shunted thereby during a small portion of the time the desired energies can reach 79 therethrough at the plurality of times when the portions 86 are opposite the corresponding po" Ions 87 of the coiiperating disk of the state killer. By suitably adjusting the speed of rotation the desired energies can be transferred to 79 substantially Without any interference from the disturbances which would otherwise render the apparatus temporarily inoperative as in the prior art. Moreover it is to be noted that in case the members 21, 22, 23 of Fig. l for example are not slotted as in Figs. 11, 12, 13 but left smooth or in the case when substantially undamped waves embracing no audible group frequency are otherwise transmitted, the device 72 85 not only serves as a static killer but also as a ticker or device to render such energy capable of producing audible effects on 79 when transferred thereto in the manner set forth, 72, 85 serving in such case to break up the energy into audible groups at the receiving station, as the rotary tuner is alternately by-passed thercbyenit again left free to absorb and transfer other energies reaching 1 as already set forth. It is accordingly obvious that I provide means to cooperate with the transmitter described to receive the energies emitted thereby to the exclusion and notwithstanding the presence of interfering energies.

In the modification of Fig. 5-shown in Fig. 10, the rotary coil 58 is inductively will be obvious from the preceding discussion that a plurality of resonant and absorbing circuits to select energy in two desired frequencies and dissipate energy in a number of other frequencies are provided. The desired energies are transferred from 3 to circuits including 3, 3 respectively via 58 while a plurality of other circuits resonant for other frequencies are also provided whereby energy may be dissipated without affecting 79 and 79 after the manner already set forth. 58 may be rotated by shaft 65 as in Fig. 5.

In the modification of Fig. 5 shown in Fig. 15, two rotating tuning elements are used. This modification provides additional absorbing, dissipating, and neutralizing circuits whereby more complex conditions than are indicated by Fig. 19 and which may occur in practice may be cared for. In this embodiment a regular circuit through 58 is adjusted so that one desired energy will be received and translated thereby, while another circuit through 58 is similarly adjusted for another desired energy. These two desired energies are respectively transferred to said circuits via 3 and 3, which are inductance coils coupled respectively thereto. The several absorbing, dissipating, and neutralizing circuits are comprised respectively by 1, 80, 54, 2; 1, 80", 55 2; 80, 80 5& 55; and the plural combinations thereof through 57 and 57 respectively after the manner already set forth for Fig. 8. The effect is accordingly the same as already set forth. are substantially avoided thereby though of course the other means herein described can be used in addition thereto as is obvious.

The modification of Fig. 16 is in all respects similar to Fig. 8 except that a vibrating detector is employed. This device is well known in the art and consists of a steel wire stretched between supports 96, 96, and contacting with a crystal 82 to form detector 78. A musically toned buzzer as 97 or 97 is broughtinear 95 to vibrate it thereby causing incoming energy in the form of continuous waves not characterized by a group frequency to be provided with a group frequency by this means at the receiver.

In the modification of Fig. 17 the two ieceiving circuits through 3", 3" respectively are connected directly through condensers Three shorter circuits are formed in 58 by connected contacts 88, 89, 90 and it All interference troubles 91, 93 with 1, 2, the static killer'72, 85 is in cluded in the manner already set forth, andadditional shunt circuits through 3, 57 and 3 areprovlded to afford the same plural 3 is preferably made with sufiicient inductance to comprise with 1 and 2 a circuit resonant to long wavelengths while 3 is adjusted -for short waves. In the modification of 22 terminals 105, 106 contact with the respective plates 72, 85 of the static killer and include an auxiliary condenser 10% as shown and the several dissipating shunt circuits tuned to different frequencies are comprised by inductances 110, 111, connected through condenser-s 112, 113 one terminal of each of which is joined by 114 as shown, 110 comprising also a condenser 57 which acts to provide a double resonance effect as explained for Fig. 8. 3 with 57 serves to transfer the two desired energies to 81 which is connected through condenser 74 with two condensers 108, 109 which have a. relatively 5 small capacity with respect to each other when the switch 115 is open and a relatively larger capacity when 115 is closed, thereby providing two circuits through 81 alter nately which are respectively resonant to the desired frequencies. 115 is operated ata musical rate by buzzer 97. A wavedetecton '7 8 and telephone receiver 79 complete the circuit, Wave detector 78 in the modified form shown in Fig. 22 has the majority of its multiplicity of contacts 77 connected with one terminal 107 and resting on crystal 82 while the other terminal of the wave detector 78 consists of the metal containing cup 98-as indicated in Fig. 20. At least one 40 of the electrodes as 77 in contact with '82 is grounded through condenser 107 as shown to provide a direct leak for any elec trostatically induced currents reaching 81 from any source. Thismodification as a whole accomplishes the results already set forth as is obvious because 'when 97 is in operation two circuits are intermittently provided through 7 4 to permit the detection of either of two energies in different wavelengths by 78 while they are also broken up into audible group frequencies, this form being preferred in case the transmitter, Fig; 1, for example 'i j'used without segmented disks as in F igs 11, 12, 13. At the same '55 time this modification provides the same plurality of means for avoiding trouble from interfering energies as has been fully set forth. Obviously at such times as not required; the auxiliary absorbing devices neednot be included in the circuit, switches 73, 73v being provided for this purpose.

. .In Figs. 8, 16, and 22 for example where stationary inductances are shown it is obvious that at least one of the inductances maybe rotated with respect to another with dissipating circuits as in the case of Fig. 5.

' prises no indication of intelligence. .fer to have the wavelengths used for dis- Which it is inductively coupled after the manner of Fig. 5, a suitable arrangement be-,

ir ig indicated by way of example in Fig. 21. Here motor 67 drives 66 which rotates inductance coil 3 provided with slip rings 4 60 Y61 and brushes 62, 63 for connection in any of the circuits mentioned. 3 is inductiv-ely coupled to 81, 81, two other inductance coils with respect to which 3 may accordingly beiapidly rotated. In Fig. 20 a suitable embodiment of the multipoint detector com rised by my inven-A tion is shown by way of example. A sensitivecrystal as galena is held by a metal cup I 98 connected with binding post 100.. A 1

large number of contacts 77 which for. ex-- ample may be metal wires or other pieces of metal-separately contact with the crystal 82, and. are held in place by the insulating support 99. A switch 103 is mounted 01199 85 with a handle arm or and terminals 102 connecting with the contacts 77. At least one of the contacts 77 may be connected with a binding post 101 as shown in order to include a resonant device as described herein-' 6" before with the detector. In the manner shown by. Fig. 20 asensitive point may be quickly found or a number of the points 77 can be connected together as in Fig. 22 to afford at least ,one sensitive contact, with 82 nd probably more than one. lnsensitive cohtactshave such a high resistance as to not adect the eiliciencybf the sensitive contacts also electrically connected therewith.'

(l ne of the contacts 77 may serve as one terminal of the detector and the remainder of the contacts as the other terminal as in Fig.

8. It is obvious that the full value of the sensitive material 82 is accordingly utilized and that various modes of connections are 5 possible as in the examples set forth. It is obvious that when my invention is in use it will be practically impossible for an ordinary receiving systemto receive an intelligible message, ifindeed, any atall.

When the wavelength only is varied in accordance with the parts of a signal, an ordinary receiving set cannot receive more than one of the parts at a time, which alone comtinction separated by a sufficient length to avoid reception of bo'th "by a dully resonant receiver. When the audible group frequency alone is varied, the advantage-of distinct signals and rapidity is secured without particular secrecy as this is desirable for instance for calling purposes, communication with ordinary stations, or for the-general" transmission of danger signals. It is not unlikely that a danger single tone or group of tones could be used as a recognized unmistakable signal for this purpose. For ex ample S. O. S. may be arranged in a distinctive combination of audible group fre- I pre- 115 uni.-

quencies by means disclosed herein such as even an ordinary Seaman could distinguish from all other signals.

lihen the trzmsl'nittcd impulses are not characterized by an audible group ,fre quency they can be received and be so characterized for distinction and translation purposes at the receiving station as set forth. The preferred mode of use however comprises distinctions in both the audible group frequencies and the radio frequencies as set forth. When it is remembered that there is a wide range oi different wavelengths. and of musical tones which can be comprised in audible group frequencies as set forth, and further that many combinations of these are possiole, and that the dividcd signal may still further be safeguard-- ed by a secret ode and the transmission of blind or coa s'ng signals, it is obvious that importa t information may be transmitted according to my invention so that cunning attempts at space tapping by unauthorized persons will have substantially no chance for success.

My, invention also provides a. system affording the very minimum of possible interference with. other stations not being com municated'with. If it is suspected that unauthorized persons have after a time ascertained the particular combinations being used the constants of the circuits may be changed to secure the same cfiect by a different combination and in fact such adjustments may be made as often as necessary. In "encral it is preferable to have the dots heard in one ear and the other differentiatcd dots representing the dashes of the code heard in the other as indicated in Fig. 8, but this is not essential. Two sensitive recorders such as two Einthoven gal- ,ranoi-ucters may be used instead of the telephone receivers in Fig. 8 for example. Heretofore the use of such recorders has been impracticable because of the slow sending speed necessary because of the slow action of the recorder. In my system with a plurality of recorders the time necessary is reatl decreased because the arts of the signal are and alternately to the two recorders so that each acts only during one half of the total time and has ample time in which to return to rest without interfering with the speed of transmission. Obviously both the telephone receivers and galvanometers or other recorders may be used at the same time if desired.

It is obvious that while preferred embodi- IUBDCS and modifications thereof by Way of example have been described, combinations as between the several. figures are possible,

it is to be noted the static killer distributed substantially equally.

increase will act as a lightning arrost er and protect the receiving apparatus.

'here in my invention. parts not before known to the art are utilized 1 have endeavored in the descriptionto state what is believed to be a probable mode of operation but as the invention resides in the combinations concerned and not in the explanations thereof the statements concerning the theory thereof are tentative and not ncccssarily precise. Various changes in the size, construction, and variations may obviously be made avithin the scope of the appended claims. While some of the alternate modified embodiments have been described by ray of example the invention is more particularly set forth in the accompanying claims.

It is of course well known that the several parts used in any wireless system, such as transformers, inductances, condensers, etc, are in themselves old and well known but the invention nevertheless resides in the particular combinations thereof whereby the new and useful objects set forth-are accomplished.

Having now described my the several details thereof, these Letters Patent are to as granted for:

1. In a wireless system, a transmitter, a receiver cooperating therewith, said receiver comprising a tuner adapted to be continuously rotated, and a wave detector associated *ith said tuner and adapted to be included in a plurality of circuits, whereby energy radiated by said transmitter may be selected and translated by said receiver while energies arising from undesired sources may be dissipated in said circuits.

2. In a wireless system, suitable receivinginductances and means including a. rotatable inductive member for selecting desired impulses therefrom.

3.111 a Wireless; system, a rotating inductance and a plurality of circuits in relation therewith, said circuits including means for selecting desired energies thereinvention and I claim, and be understood from and for dissipating other energies.

i. In a wireless system, a transmitter comprising a wave generator consist-ingot a plurality of electrodes in close proztimlty to each other and having a relative motion in the presence of a cooling insulator, means for varying the audible frequency of said generator, means associated with said genorator whereby energy may be radiated, in different and distinguishable wavelengths, to represent signal elements, a receiver comprising a wave detector, tuning means associated with said detector to select and supply it with energy from said transnntter, means associ ted therewith to cause said received energy to indicate said transmitted signal elements, means associated rumpus with said receiver to guard said detector from and. dissipate other energies reaching said receiver in other greater and lesser.

wavelengths, andauxiliary means to short circuit said recelver at suitable times when necessary to bypass energies arising from strong atmospheric disturbances in the v1- cinity of said receiver without preventing the reception of said transmitted energy.

5. In a wireless system; a transmitter comprising 'means for radiating energy and -me ans to modify the wavelength and audible frequency thereof; a receiver having 7 means to select and render intelligible energy received from said transmitter, said meansv comprising a' continuously rotatable tunin memben. 4

8. a wireless system, a receiver comprising a ground terminal, a conductor having capacity, with respect thereto, an inductance connecting said ground terminal and conductor, a condenser connected in shunt witha portion but not all of said inductance whereby two circuits are formed, theoncthrough said inductance alone and the other through a portion of saidinductance in series with the reactanoe formed capacity shunted thereabout, a second inductance coupled to the aforesaid inductance and connected with, a condenser to form asecondary circuit resonant with one of the aforesaid circuits but not the other, adetector, and an indicator associated withsaid secondary circuit.

7.111 a wireless system, a transmitter, a

' re eiver, said receiver including a rotary tuning member comprising inductances having a continuous relative motion with respect to each other whereby said receiver mayselect radiant energy emitted by said reaching it.

transmitter ,anddissipateother energy 'f 8.1'In a wireless system; a transmitter comprising an oscillat on producer includmg an, nductance, a second. inductance coupled thereto and connected between a ground terminal and a conductor having .forming a secon capacity with respect to the ground, thereby radiant energy flows and from which it is radiated, a switch to conductively connect said second inductance to said oscillation producer whereby distinguishable signal elements' may be transmitted; a receiver comuprising a. wave detector and means asso:

-. ciated'therewith for making said signalelements'manifest, anda rotating member.as-

sociated with said receiver to exclude un desired impulses therefrom.

'9 A wireless signaling system including means for dividing the signals into recog-' nized portions, a plurality Of-lIIttBIChQIIgG- able circuits having a common rotating. electrode, means associated with said electhe remainder of said inductance andary circuit through which trode whereby a difierent radio and audible frequency energy is caused to flow in each of said circuits, means for severally transmitting the said portions through the inter- Jchangeable circuits, a receiving station having circuits corresponding to said'interchangeable circuits, means associated theremanifest, and auxiliary means at the re'. ceiving station to dissipate energies coming thereto from other stations and arising from atmospheric disturbances.

lQrln a Wireless system, a receiver comprising suitabletuning means and av wave detector, means for conveying intelligence to a human operator associatedwith said detector, and an auxiliary inductance. not

comprised in said tuning means but shunted about a portion of said wave detector whereby the characteristics of said detector may be altered without adjusting, 'changing, or moving the electrode terminals by which said detector is connected with said tuning means.

11. In a wireless signaling system, a re ceiver comprising suitable tuning means, a Wave'detector, and an indicator, said detector consistin of a sensitive crystal, a large number of electrode surfaces contact- -ing therewith, and means independent of said contact between said crystal and electrodes.

13. In .a wireless system, a receiver includin a wave detector comprised by a 'crysta having a number of metal points in contact therewith andan inductance coil inwvith to render said transmitted signals dependent of said recelver. andconnecting at least two of the metal points.

14. In a wireless communication system,

a receiver comprising tuning elements and a wave detector, said detector comprising a sensitive crystal contacting with a number of separate pieces of metal and an inductance coil independent. of said tuning means connected between any two of said pieces of metal. i

15. In a wireless communication system, 'a receiver comprising a. plurality of .in-

ductance coils having, s regards each other,

a negligibly small percentage of coupling, a closed circuit inductance coil having a relatively large percenta gev of coupling with respect to, at. least one of said inductance coils, a wave -.detect0r connected to said closed mductance, means associatedtherewith, to suitably indicate energy reaching said wave detector, said plurality of inductances being connected between an elevated conductor and the ground respectively to form a plurality of circuits therebetween and said closed inductance being used to select energy from at least one of said circuits.

16. In a wireless communication system, a receiver comprising two inductance coils connected in parallel and between the antenna and ground respectively of said receiver and having a small percentage of coupling with respect to each other, an in-- ductance coil associated therewith and adapted to be continuously rotated, and means associated therewith to translate received energy.

17. In a Wireless communication system, a receiver comprising an antenna, a ground, a tuning member connected therebetween, a cooperating tuning member associated therewith and adapted to be continuously rotated with respect thereto, and means associated therewith to detect and translate desired energy reaching said receiver.

18. In a wireless communication system, a transmitter comprising a current source, circuits and a discharge member connected therewith, said discharge member comprising a revolving disk carrying two sets of discharge surfaces, the one having a greater number thereof than the other, two electrodes in close proximity to said disk in the presence of a gaseous medium under pressure, two oscillatory circuits respectively including said electrodes and embracing respectively the said two sets of discharge surfaces on said disk, a radiating circuit associated with said oscillatory circuits, means to transmit energy representing a dot of a code via one of said oscillatory circuits and for transmitting energy representing a dash of a code via the other oscillatory circuit, and a receiver comprising means 'for selecting and translating said energies reaching it from said transmitter.

19. In a wireless communication system, a transmitter comprising a current source and circuits connecting it with a pair of discharge gaps each of which includes an oscillatory circuit having a diHerent period than that of the other, means for simultaneously rotating at least one electrode of each of said gaps in the presence of hydrogencontaining gas, means for obtaining a different audible group frequency from each of said gaps and their associated circuits, and a radiating circuit coupled to each of said oscillatory circuits, and a receiver comprising means for absorbing, selecting, and translating energy radiated to it from said transmitter in either of the group frequencies and periods.

In a. wireless communication system, :1

transmitter comprising a source of electrical energy, circuits respectively connecting a 1'0- tating electrode and two cooperating electrodes therewith, a gaseous medium under pressure between said electrodes, a pair of circuits each containing different values of inductance and capacity connected arouni said electrodes, a secondary and radiating circuit inductively coupled thereto, and a receiver comprising circuits to select ener gies reaching it from said transmitter and translate them into sound waves.

21. In a wireless communication system, atransmitter comprising a source of electrical energy, circuits respectively connecting a pair of discharge gaps therewith, said discharge gaps comprising respective sets of uniformly spaced electrodes carried by a rotating disk in close proximity to coiiperating electrodes in the )resence of a cooling dielectric whereby di erent musical tone effects are secured when using the respective gaps with their different sets of electrodes, a. 011'- cuit containing .inductancr and capacity connected with said gaps and with a radiating circuit, and a receiver comprising means to select and translate energy reaching it from said transmitter when transmitted via either of said gaps.

22. In a wireless communication system, a receiver comprising means to select, detect, and translate desired radiated energy reaching it, and auxiliary means for alternately short circuiting and again operatively connecting said selecting means at a rate rapid enough not to prevent the reception of the desired energy, to bypass said selecting means, for protectimrfrom energies reaching the receiver and arising from strong atmospheric disturbances.

23. In a wireless communication system, a receiving set, an antenna and a ground terminal connected thereto, and a device shunted about said receiving set comprising means to connect said antenna and ground through a direct auxiliary circuit and disconnect]san1ei alternately ata rate which does not "pr hit the reception of desired signals. i i

24. In a wireless system, a receiving set, an antenna andj a ground terminal respectively connectedjthereto and means for dissipating static charges as they accumulate intermittently connected in series with said aerial and ground at a rate which does not prevent the reception of desired signals.

25. In a wireless communication system a transmitter comprising meansto radiate a pluralit" of differentiated groups of wave trains representing respective elen ents of a signal and including a segmem d rotary gap dischargcr adapted to impart distinguishable musical tones to each of said groups, and a receiver comprising means to select each of said groups of wave trains Signed at Minneapolis, Minn., this 14th which reach it and translate them into intelday of August, 1912.

ligible sound waves and auxiliary means t9 PHI IP E. EDELMAN. neutralize and dissipate undesired energies Witnesses: 5 reaching said receiver from other transmit- ANNETTE MARTINsON,

ters and from atmospheric disturbances. MEYER I. EDELMAN. 

